Solid fuel for lighters



Patented June 6, 1939 UNITED STATES PATENT OFFICE No Drawing.Application October 2, 1937, Serial No. 167,077. In Austria October 7,1936 4 Claims.

This invention relates to a solid fuelfor lighters. The disadvantage ofthe known benzine lighters is that the fuel evaporates for the most part6 during use and ,makes it necessary to reflll'the lighter from time totime. Attempts have therefore already been made to use solid fuels forspark operated lighters without however achieving any results ofpractical use which would have enabled 10 such lighters to replace thewell known benzine lighter.

Inter alia it has also been proposed to use met-- aldehyde and to scrapepowder from the surface of the rod before using the lighter, the powder45 and with it afterwards the rod being ignited by means of a spark (seeSwiss Patent No. 108,322). Reliable ignition of the rod by a singleshower of sparks could not however be obtained in this way. Atomisationwas also disadvantageous. It has also been suggested to use solidmixtures of the fuel proper with considerable quantities of vigor-'ously burning substances as the igniting agents. Thus for example (seeSwiss Patent No. 174,405) it has already been proposed to use a mixtureof fuels, such as about 80% of naphthalene or camphor, with considerablequantities of powdered or short fibered nitrocellulose, say about 20% ofthis latter. This mixture was intended to be compressed and the fibrousnitrocellulose laid bare at the particular end of the bar beforeignition by a roughing up device. This proposal is however quiteunsuitable'in practice and hastherefore never been put into practicaluse. The reason for this is that such quantities of nitrocellulose lead35 to various inconveniences in manufacture and storage and also in use.On the other hand naphthalene, camphor or similar products gives anexceedingly smoky flame and a disagreeable smell, which is particularlymanifest when large quantities of this substance are used. Finally thissubstance gives rise also -to inconveniences when kept in the pocketduring use. n the whole it is quite impossible to replace the highlydeveloped benzine lighter or the benzine by a material which has so manydisadvantages. It has already been proposed also (see German Pat ent No.543,023) to use pressings composed of mixtures of metaldehyde with fromto 50% of nitro bodies of various kinds in form of powders for thispurpose. It is impossible, however, to obtain a fuel which can beignited with even a fair degree of reliability by a shower of sparkswhen the above substances are used, as the presence of nitro compoundsis not sumcient. They cannot replace the effect of materialswhich re-'duce thermal conductivity like fibres (the necesf i offlwhich was notrecognised when this proposed was made) nor the nature and qualitiesFor. the fuel which can only be obtained by such admixture." If forexample of nitrocellulose I iin'a dissolved and therefore finest form heinti- "m'ately mixeclwith metaldehyde and the product mouldedand dried,no perceptibly better eflect as regards infiammability by a spark, canbe detected in comparison with moulded bodies which 10 consist ofmetaldehyde only. The same remarks apply to other nitro compounds whichhave been suggested, namelynitro starch, nitrophenol and the phosphoruscompounds mentioned, which latter also have otherjdisadvantageousproperties. 1 'Besides, if large quantities. of ':nitro compounds beemployedthey 'leadto the disadvantages hereinabcve referred to;'Thissuggestion also was useless in practice and was never used in theIt has also been proposed (see French Patent No. 666,838) to envelop atextile wick impregnated with greasy substances in wadding provided withnitro cellulose, potassium chlorate or alcohol and to cause such a wickto ignite by 2 sparks instead of benzine. This suggestion also isworthless in practice.

' All the many experiments which have been made to endeavour to solvethe problem of the production of a solid fuel for a lighter operated byspark ignition go to show how very greatly the need is felt in expertcircles for replacing the volatile benzine with all its disadvantagesconsequent upon its volatility by a solid fuel and how difficult it hasbeen on the other hand to do so seeing that no one has succeeded fordecades past. in finding a satisfactory solution of this problem.

Mention may also be made of proposals for the production of solid fuelswhich contain acore of oxygen salts and which are intended to be ignitedin lighters by means of suitably arranged frictional surfaces containingphosphorus. Fuels of this kind, however, relate toan entirely diiierentpurpose and are based upon a differently acting mechanism and they canno more be caused to inflame 45 by sparks from pyrophoric metallicalloys than can ordinary'metaldehyde rods or sticks, as they do notcontain fibres.

The use of fibres in under lighters is also known. This is, however,such a totally different technical 5o branch that, as the suggestionspreviously made during the last decades clearly show, the solution ofthe old problem connected with lighters by using the fibres used inunder lighters, doesnot belong to the range of average technicalknowl-,-

edge, apart from the fact that it must also appear quite' un certainwhether the fibres used in under lighters would enable the problemswhich arise in lighters to be satisfactorily solved in view of thetemperature and other conditions which prevail in the case of a lighter.

According to the present invention, therefore, it is now possible toproduce a solid fuel for spark operated lighters which is not volatilein practice, that is to say, does not exhibit the disadvantages ofbenzine lighter, can be just as reliably ignited as a benzine lighter,can be easily, reliably and quite safely handled and burns with anon-sooty, steady and satisfactory odourless flame and can also beeasily extinguished.

It has been now found that for the solution of the present problem agreat improvement in comparison with the known moulded bodies frommetaldehyde can be achieved by reducing the thermal conductivity of themoulded bodies composed of metaldehyde. This may be convenientlyaccomplished by the addition of substances, which are bad conductors ofheat, to the metaldehyde, as the inflammable substance, i. e., thesubstance which above all things maintains the flame. Such substancesensure that the thermal energy of the impinging spark is not carried offto a deleterious extent but is utilised to heat the spot on which itimpinges to the temperature of ignition. As substances which reduce thecoefficient of thermal conductivity, use may also be made of kinds offibres which burn well, particularly textile fibres of low thermalconductivity, also finely ground and well dried cork meal. The reductionof the thermal conductivity is also assisted by a suitable structure ofthe rod or stick, which preferably should not be made denser than isnecessary in view of the amount of strength desired and taking intoconsideration the addition also of a possible covering or coating.

The part which thermal conductivity plays has also been discoveredthrough a further observation, which is that if metaldehyde dust isproduced say in large quantity in a deeper opening in the rod or stickby the use of a roughing up device which works at a greater depth andacts somewhat like a drill and the spark be allowed to impinge at thispoint, the powder will ignite,'provided that the loose quantity of dustis so great-that it will act as a heat insulator for the spark incomparison with the pressing which conducts the ,heat away to a greaterextent.

It has also been observed that important advantages can be obtained if,in addition, the particles of the inflammable substance produced whenroughing up are held together in a loose state at the place where theroughing up takes place by combustible retaining devices such asa'sufiicient quantity of long fibres. In many cases 7% for example offine cellulose fibres,

say artificial silk fibres about 0.6 cm. long for- The fibres consistpreferably of such organic material as say, cellulose, which does notyield undesirable products of combustion, or not to any objectionableextent.

The fibres of materials which it is preferable to use and which consistof substances which do not explode and do evolve objectionable productsof combustion when burned, differ advantageously from the fibrousnitro-cellluose which is mentioned in Swiss Patent No. 174,405 as aconstituent of the mixture composing the rod or stick, the maincomponents of which differ from those used here and which are useless inpractice. It has now been found that it is not necessary to use fibrousnitrated cellulose as an igniting agent and consequently to have to putup with the disadvantages which are connected with the use of largequantities -of nitrated cellulose and which cause the evolution ofconsiderable quantities of undesirable products of combustion, thedanger of spontaneous ignition and ethers. It has also been found thatit is much more important and that it suffices to reduce on the one handthe thermalconductivity of the mixture byfibres which are bad conductorsof heat so that the thermal energy supplied by a single shower of sparksis sufficient to produce the necessary increase of temperature andtherefore the reliable ignition of the place at which the sparkimpinges, and on the other hand to afford the spark a surface at thepoint where the fuel is roughed up which is formed by pulverulentparticles and fine fibres and is comparatively large, the particleswhich are formed by the roughing up of the fuel being held together andprevented from falling off. On the other hand the present inventionshall not be evaded by adding to the material, according to thisinvention, a small quantity of nitrated cellulose or by replacingtherewith partially or wholly the fibres of ordinary cellulose. Theprotection sought is therefore intended to include such inferior formsalso because fuels for lighters operated by spark ignition composed ofaldehyde derivatives and fibrous nitrated cellulose have not beenproposed heretofore, and are, even if they only constitute an inferiorproduct in comparison with the real and preferable embodiment of thepresent invention, a considerable improvement on the present state ofthe art. If this constructional form with nitrated cellulose be desired,undenitrated or only slightly denitrated Chardonnet silk may be used.

Cellulose artificial silk has proved to be particularly useful,especially when it is used as a very fine fiufil This can be obtained bycutting up and teasing out the cut up fibres by means of suitableappliances, such for example as brushes revolving towards each other, ifit is not preferred to use untwisted single threads as the raw material,which can be obtained by the omission of corresponding stages ofmanufacture in the production of artificial silk. The length of thefibres is not of paramount importance. Long fibres are advantageous invarious ways, but the length will not go so far according .to the methodof manufacture selected that uniform distribution will meet with anydifificulty when the fibres are mixed. In many cases fibres to 1 cm. inlength have been found very suitable. The use also of short fibres to beworked into the mixture first, say before granulation, if such beundertaken, and also of longer fibres to be added afterwards, mayfrequently be advantageous.

In some modes of procedure, other natural or artificial fibres orthreads than the preferably used artificial silk fibres, can also beused or used 2,1e1,see

conjointly with them, such as cotton or other vegetable fibres forexample, well teased out wadding fibres or thin squirted artificialthreads, also those of suitable artificial resins, although an increaseduse of substances which, owing to their chemical constitution orexcessive thickness. brings about disadvantageous phenomena such as abad smell or residues left after combustion, and makes the fuel to beproduced less suitable or even unsuitable for the present purpose.

The substances which really support or maintain the flame (theinflammable substances) are preferably also incorporated in the mixturein the finest possible state of subdivision. As such inflammablesubstances the various aldehyde derivatives known for solidified spirit,such in particular as metaldehyde, are used. This, however, may be alsopartially replaced in somemode of procedure by other materials and ingreater measure the better these substitutional substances are suitablefor the purpose per se, and the more they burn without smoke, smell andresidue, such as in particular various other organic substances whichwhen heated sublime with or without decomposition, and preferably thosewith groups which contain oxygen and which burn without evolution ofsmoke and without leaving melts or carbonaceous residues.

For example, in some cases polyglyoxal, trioxymethylene,hexamethylenetetramine, certain quinones can be used in smallquantities. Metaldehyde is, however, preferable.

According to this invention binding agents are also used. The bindingagent must be capable of imparting to the fuel the amount of strengthnecessary to withstand the mechanical strain put upon it by the lighterand it must also accord with and co-operate with the nature of themoulding of the rod or stick of fuel and any covering or coating whichmay be applied thereto. The presence of at least small quantities ofbinding agent is preferable, also because of the reason that pulverulentparticles of the inflammable substances shall adhere by means of a thinfilm of the binding agent to at least a portion of the fibres exposed bythe roughing up device since such pulverulent particles, like thosewhich are detached, assist in the reliable ignition of those particlesof the inflammable substance which are only'mechanically held by thefibres of the fluff, apart from the fact that loss of substance when thefuel is roughed up again is more avoided.

In the proposals above mentioned, which relate to fuels adapted to beignited by means of sparks from pyrophoric metallic alloys, bindingagents were not otherwise used, obviously because it was desired tomould the composition from extremely inflammable materials whileavoiding inert binding agents. It has, however, been unexpectedly foundthat organic binding agents of low inflammability by no means impair theignition of the whole mass owing to their fine state of sub-division.The mostv varied kinds of organic binding agents can therefore beemployed.

The binding agents may be added in a dissolved form but the cohesion canbe effected without solvents by using binding agents of the desiredcomposition which set at ordinary or higher temperatures under slightpressure, such for example as stearin gelatine, gum arabic which set atordinary temperature or thermoplastic binding agents which soften andbecome adhesive at higher temperatures.

In many cases it may be suitable to mix the mixture first with asolution of a binding agent and to granulate and then to press thethoroughly dried grains. In such case only short fibres may be addedbefore granulation and the grains then pressed together with longerfibres.

Both water-soluble binding agents and those which are soluble in organicsolvents may be used. In the case of water-soluble binding agents caremust be taken to see that the rod is well dried before any coating isapplied to it.

Only such binding agents are also preferably employed which do notattract moisture from the atmosphere to an inconvenient extent under theparticular climatic conditions which may prevail. Good results wereobtained with bead glue for example. In many cases, however, thewater-soluble binding agents known in the manufacture of tablets, suchas gelatine or gum-arable may be used or used with others. Water-solublecellulose compounds may also be used, such for example as Cellofas. Fordamp climates, however, the latter binding agents are less suitable. Asbinding agents which are soluble in organic solvents, nitrated celluloseor solutions thereof forexample may be used and best those with a lowdegree of nitration, such as is usual for varnishes. Acetylcellulose,for example, may however also be used, or resins in alcoholic solution,such as spirit varnishes.

The proportions of the ignition substances. that is, of the fibres andthe inflammable substances (such as metaldehyde preferably) vary withinwide limits, within which the action of both is still present. Theremust therefore be at least as much fibres present that ignition by meansof sparks will still take place under the given conditions.

In the preferred mode of carrying out the invention the inflammablesubstances, such as metaldehyde in particular, are in preponderantquantities and may with advantage be more than 70% relatively to theweight of the rod.

The most favourable quantity of fibres depends on their nature and onthe possible conjoint use of other substances which reduce thermalconductivity. In most cases a quantity of fibre less than 10% would besuitable. In the preferable modes of procedure in which fibres only areused, a percentage of fibre of about 7% has been found very favourablewhen well teased out artificial silk is used. 1

The specific volume of the fuel should be greater by 20% and preferablyby 50% than if the inflammable substance metaldehyde were pressed underpressure by itself.- The specific weight of the moulded products ispreferably less than 1.

It is desirable that the inflammable substances and the fibres should beused simultaneously in practically sufiicient quantity and that thereshould not be a lack of inflammable substances which would cause theaccumulation of quanti- -ties of carbonaceous fibrous residues, evenwhen vention, the amount of binding agents employed is less than 7% (thedry substance of the binding agent calculated on the mass of the rod).This quantity may also be exceeded but roughing up must not be madedifficult or the production of slightly coated fibres at the roughing uppoint which is still sufficient for ignition prevented. The amount ofbinding agent is always less than 20%.

In some forms of carrying out the invention with a looser core. it isconvenient to use more binding agent in the outer layers than in theinner layers or to add more binding agent in the outer layers by coatingwith solutions of binding agents. In some binding agents it isconvenient to granulate first in some way and then to spray with asolvent which in the cold only moistens but when used hot causes thebinding agent to swell up, so that any admixture of long fibres to thecores is facilitated and greater cohesion obtained on subsequentpressing.

The binding agents used should be fairly brittle at ordinary temperatureand therefore facilitate the subsequent roughing up when the lighter isused by the formation of extremely fine particles. I

In many cases it is advantageous to add to the fuel compounds whichwhile it is burning evolve oxygen, preferably organic compounds, such asbenzoyl superoxide for example which inter alia also improve the smell.Preferably about 3 to 6 per cent. of benzoyl superoxide are used. Theoxygen compound added favours the complete combustion of the fibres.Such large quantities as would make extinction difficult must not,however, be added, or so much as would cause any considerable evolutionof smoke after extinction.

Other additions to the fuel may be made which improve the effects orbring about desirable subsidiary effects. Thus for example substanceswhich improve the smell while thelighter is burning and after the flamehas been extinguished, such as suitable crystallised perfumes, essentialoils etc. may be added in small quantities, and/or if desired additionsmay be made which affect the colour of the flame. When essential oilsare used the vapour tension thereof may be reduced by the conjoint useof viscous substances which are miscible with the essential oils orwhich dissolve them,'such as a fatty acid, so as to enable the perfumeto keep better when stored for a long time. An essential oil which canbe used with good results is oil of lavender. As a crystallisedartificial perfume borneol or the more easily subliming isoborneol, butif desired artificial xylol musk, Jara-Jara and other artificialperfumes may be used conjointly in small quantities, but preferablythose which at least sublime partially and therefore leave but littleresidue when they burn. If balsams and pleasant smelling resins be usedconjointly they must be used in such small quantities that when they areused they do not melt which would prevent the lighter from being lightedagain.

As additions which affect the colour of the flame, salts may be usedinter alia, the actions of which impart to the flame a well known brightflame colouration, such for example as sodium salts, which colour ityellow, calcium salts which give it a reddish colour etc. For example,an addition of 1% of calcium stearate produces a flame eolouration whichis frequently regarded as desirable.

It is advantageous to give the stick or rod a coating consisting of oneor more layers of col- ,st-and protracted lodion for example so as togive it greater strength and to protect it from external influences,particularly moisture, to enable it to withstorage and for otherpurposes.

Admirable results can be obtained with sticks or rods produced in thisway. The feed necessary from time to time can be obtained with all kindsof brake apparatus as no parts which would interferewith this operationare present which would be melted or softened by the heat of the flame.

In modified constructional forms which, however, are less advantageous,the fuel may also be used in form of flexible wicks. For this purpose itmay contain as the flexible carrier material, fibres or threads of stillgreater or continuous length.

In other modified forms it may also be used in the form of thin bands orfilms in lighters adapted for this form with suitable feeding oradvancing devices.

The constructional examples:

(1) The materials used are- Per cent Metaldehyde 85 Fine artificial silkfibres 7 Benzoyl superoxide 3 Collodion (dry substance); 5

simultaneously intimately mixed, compression. and agglomeration of thefibres being again avoided as much as possible.

The mass is then moulded into slabs on a smooth support. This may beconveniently carried out with the use of pressure or by lightly beatingor patting the mass. The slabs are cut up into sticks or rods as soon asthey are sumciently dry and are afterwards dried completely. Afterdrying they are dipped into a 6% collodion solution, which in order toavoid confusion in such rods may contain a gaudy colouring matter, sothat such rods shall exhibit a characteristic colour which will notescape attention. If desired the rod may also be coloured throughout itswhole mass, for which purpose Zapon colours are well suited.

(2) If it be desired to colour the flame slightly, say red by a calciumsalt, and/or if it be desired to perfume the rod so as to make the smellof the metaldehyde which is particularly noticeable when the flame isextinguished, the following mixture may be used:

The oil of lavender is preferably mixed first with the fatty acid andboth then intimately stirred into the mixture compounded as above.

(3) In the mixture according to example 1 only 1% of artificial silkfibres and 6% of the finest dry cork meal are used instead of 7% ofartificial silk fibres.

The cork meal may be reduced to a particularly fine state ofsub-division in the dry way by means of ball mills for example, but alsoif desired in an aqueous suspension using homogenising jets andsubsequent drying. In this way an embodiment of the invention isobtained which can be easily moulded, but is inferior in respect ofcombustion free from residue yet is a form which can be usednevertheless.

What I claim is:

1. Spark-ignitable solid fuel for pyrophoric lighters consistingessentially of a molded intimate and substantially uniform admixture ofa member of the group consisting of the combustible non-fusing aldehydesand non-fusing derivatives thereof in finely-subdivided solid form asthe major flame-supporting constituent, and of finely dividedcombustible fibrous material of low thermal conductivity and low burningvelocity and also a combustible organic binding agent as minorconstituents, said solid fuel being roughenable at a spark-impingingportion with only partial detachment of finely-subdivided combustibleparticles and with simultaneous substantial fiuifing of thecorresponding fibrous material, the resultant fiufiy fibers constitutinga retaining framework for the said detached combustible particles,whereby the spark-impinging portion comprises a spark-ignitableintermingling of combustible particles and fibers of enlarged surfacearea.

2. Spark-ignitable solid fuel for pyrophorici lighters consistingessentially of a molded intimate and substantially uniform admixture ofmetaldehyde in finely-subdivided solid form as the majorflame-supporting constituent, and finely-divided combustible fibrousmaterial of low thermal conductivity and low burning velocity and also acombustible organic binding agent as minor constituents, said solid fuelbeing roughenable at a spark-impinging portion with only partialdetachment of finely-subdivided combustible particles and withsimultaneous substantial fiufiing of the corresponding fibrous material,the resultant fluffy fibers constituting a retaining framework for thesaid detached combustible particles, whereby the spark-impinging portioncomprises a spark-ignitable intermingling of combustible particles andfibers of enlarged surface area.

'3. Spark-ignitable solid fuel for pyrophoric lighters consistingessentially of a molded intimate and substantially uniform admixture ofmetaldehyde in finely-subdivided solid form as the majorflame-supporting constituent; and of finely-divided combustible fibrousmaterial of low thermal conductivity and low burning velocity and also acombustible organic binding agent as minor constituents, said fibrousmaterial consisting essentially of artificial silk fibers, said solidfuel being roughenable at a spark-impinging portion with only partialdetachment of finelysubdivided combustible particles and withsimultaneous substantial fiufling of the corresponding fibrous material,the resultant flufiy fibers constituting a retaining framework for thesaid detached combustible particles, whereby the sparkimpinging portioncomprises a spark-ignitable intermingling of combustible particles andfibers of enlarged surface area.

4.;spark-ignitable solid fuel for pyrophorio lighters consistingessentially of a molded intimate and substantially uniform admixture ofmetaldehyde in finely-subdivided solid form as the majorfiame-supporting constituent, and of finely-divided combustiblefibrousmaterial of low thermal conductivity and low burning velocity and also acombustible organic binding agent and benzoyl superoxide as minorconstituents, said solid fuel being roughenable at a spark-impingingportion with only partial detachment of finelysubdivided combustibleparticles and with simultaneous substantial fiufiing of thecorresponding fibrous material, the resultant fiufiy fibers constitutinga retaining framework for the said detached combustible particles,whereby the sparkimpinging portion comprises a spark-ignitableintermingling of combustible particles and fibers of enlarged surfacearea, said solid fuel containing about to about of metaldehyde. about 7to about 10% of fibrous material, about 5 to about 20% of binding agent,and about 3 a to about 6% of benzoyl superoxide.

FERDINAND RINGER.

